Erdogan had also called for a truce, but Putin said this would be pointless as it would not involve the Islamist militant groups that Russian Federation deems terrorists, and Rouhani said Syria must regain control over all its territory. They say they are targeting terrorist groups.
Government forces, backed by Russian Federation and Iran, have been massing troops for weeks in preparation for an attack on Idlib province that is the last major rebel stronghold in the country.
Having retaken the suburbs of Damascus from the armed opposition, and regained control over Daraa - the cradle of the 2011 uprising that morphed into Syria's seven-year civil war - Syrian President Bashar al-Assad has now set his sights on the country's northern provinces.
Already hosting 3.5 million Syrians - the world's biggest refugee population - Turkey says it can not absorb more victims of the war and has accused the West of abandoning it to face the consequences of President Bashar al-Assad's reconquest of Syria.
"Film crews from several Middle East TV channels and also a regional branch of a leading USA news TV channel arrived in Jisr ash-Shugur this morning for filming".
But he stressed that "there are 100 civilians, a lot of them women and children, for every fighter in Idlib".
But there is a further obstacle; the strip of land between Turkey-controlled Afrin and Idlib is controlled by Hayat Tahrir al-Sham (HTS), a former al-Qaeda affiliate.
Among this patchwork of opposition are over three million civilians.
It is home to some three million people - around half of them displaced from other parts of the country, according to the United Nations.
USA ambassador Nikki Haley accused the regime's main backers of escalating the violence in Idlib province and using terrorist tactics.
They have also sought to emphasise the threat of militants, using language that hinted at the conduct of the coming battle, with foreign minister Sergei Lavrov describing them as a "festering abscess" that must be "liquidated".
"We invite the worldwide community to vocally and actively support our efforts to this end", Sinirlioğlu told the U.N. Security Council during a session on the Syrian province. "Idlib is the last so-called "de-escalation zone" in Syria", Guterres said. On September 20, the UN envoy is expected to present a report about developments concerning the Syrian political process to the United Nations Security Council.
Moscow will once again use its propaganda capabilities to obfuscate and promote its own interests, reneging on deals when the time is right.
"It is a very major preoccupation for us", Lowcock added. With decisive Iranian and Russian help, Assad has now recovered most of Syria.
Erdogan said that a focus on the potential use of chemical weapons alone was not enough. The US is concerned they could eventually be used to launch another chemical attack as well as a conventional assault.
The escalating bombardment has already damaged civilian infrastructure.
In a southern part of Idlib, a anxious father busied himself making homemade gas masks, by stuffing gauze, cotton wool and coal into paper cups, then placing them in the corner of a large plastic bag.